How the concentration of brine affects the conduction of electricity.

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Electrolysis Investigation

Aim: How the concentration of brine affects the conduction of electricity

Background Information:

Electrolysis: Metals that are more reactive than carbon are extracted by electrolysis.

Electrolysis is the break down of a substance by electricity.  Electrolysis only occurs in when an ionic substance is molten or is in solution. A substance that can be electrolysed is called an electrolyte.  Electrolytes are made up of ions. Electrolytes need to be molten or in solution, so that the ions present are free to move.

Ionic compounds have high melting points, so it is often easier to electrolyse the solution of the ionic compound.

When the electrodes are connected to a source of direct current one, called the cathode, becomes negatively (-) charged while the other, called the anode, becomes positively (+) charged. The positive ions in the electrolyte will move toward the cathode and the negatively charged ions toward the anode. This migration of ions through the electrolyte constitutes the electric current in that part of the circuit. The migration of electrons into the anode, through the wiring and an electric generator, and then back to the cathode constitutes the current in the external circuit.

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Concentration: The concentration of a mixture also effects the rate of reaction.  An increase in concentration means there are more particles. More particles means there will be more collisions. This should increase the reaction rate.  

Concentration may be expressed in a number of ways. The simplest statement of the concentrations of the components of a mixture is in terms of their percentages by weight or volume.

Apparatus List: Power Pack, Electrodes, Beakers, Sodium Chloride, Spatula, Water, Measuring Cylinder, Ammeter, Weighing Scales

Diagram:

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The apparatus list layout looks slightly messy, it should be tidier and presented in bullet points. The diagram does not appear in the PDF. Punctuation, spelling and grammar are all to a good level.

The candidate explains the background of the experiment very well, and explains how concentration may affect the experiment in simple and concise terms. The candidate does not explain what brine is from the start which would be good so their understanding of what brine is becomes clear. It would be more correct to use the term NaCl. The candidate should expand on why they are keeping certain factors constant in the fair test section to show their understanding on how different factors may affect the results. Their prediction is good and takes into account the background researched. They provide viable ways to improve the experiment in their conclusion. Decimal places are kept consistent which is good.

The focus of the question is done well. The question shows good underlying research and predictions throughout the experiment. To improve, they should consider further improvements that could be done to make the experiment more reliable.